Answer to Activity 5
Some functions could be described in sentences like:
Gets orders from customers and receives payment when they are delivered.
We can show this as a Level 1 DFD:
Note that the data flows from the Level 0 DFD are attached to the correct Level 1 function.
However, we are not quite finished with this diagram yet. There are certain rules we must learn in order to ensure that we create a valid DFD. Here they are below - it is recommended that you learn these well!
Rule 1 - Does each function have input and output?
Rule 2 - Does each function have all the information it needs in order to produce its output?
Rule 3 - If not, then what information does it need and where will it get that information from?
Next: Applying the Rules